The present invention is generally related to resilient clamps for closing flexible hoses of infusion, transfusion and the like equipment.
More particularly the invention is directed to a resilient clamp of the type comprising a body forming in one single piece an upper arm, a lower arm and a curved end portion having a substantially semi-circular shape and elastically interconnecting the upper and lower arms. The lower arm is provided on its side opposite to the curved end portion of the body with an elastic branch bent towards the upper arm and having an anchoring member, and the upper arm is provided, also on its side opposite to said curved end portion of the body, with a maneuver portion and an anchoring element complementary to said anchoring member of the elastic branch of the lower arm and releasably engageable with the anchoring member. The upper and lower arms are further formed with respective juxtaposed clamping projections facing towards the inside of the body and displaceable between a mutually distal position, corresponding to a disengaged condition between said anchoring member and said anchoring element, and a mutually proximal position corresponding to an engaged condition between said anchoring member and said anchoring element. The curved end portion of the body and the elastic branch of the lower arm are formed with respective apertures defining a passageway for a flexible hose fitted through the body between said upper and lower arms.
Resilient clamps of the above-referenced type are since long produced and successfully marketed by the Applicant. In use, in order to perform clamping of the hose fitted through the clamp body, it is sufficient to press a finger onto the maneuver portion of the upper arm, so as to bring it near to the lower arm by virtue of the elastic deformation of the curved end portion of the body, up to engagement between the anchoring element and the anchoring member, due to their mutual snap coupling following elastic deflection outwardly of the bent branch of the lower arm. This operation produces displacement of the inner clamping projections of the upper arm and of the lower arm from their distal position to their proximal position, thus clamping and throttling the flexible hose.
The conventional clamps of the above referenced type are affected by several drawbacks from both the functional and ergonomical point of view, i.e. in connection with operating thereof by the user. These drawbacks derive from a partially inadequate structural conformation of these known clamps owing to the reasons listed in the following.
Firstly, in the known clamps the maneuver portion of the upper arm is located flush with or in any case substantially at the same level of the anchoring element carried by the upper arm. In use, in case the nail of the user's finger pressing against the manoeuvre portion is projecting beyond the end of the upper arm, upon snap engagement between the anchoring element and the anchoring member the nail itself may be broken, with an evidently painful consequence. Moreover, for the same reason, in the engaged condition between the anchoring element and the anchoring member the elastic branch of the lower arm is projecting above the upper arm and is thus exposed to the risk of accidental disengagement.
Secondly in the above conventional resilient clamps the clamping projections for the flexible hose are located substantially in correspondence of the centre of the body, whereby the lever arms on which the user's thrust is applied, i.e. the portions of the upper arm and of the lower arm comprised between the respective clamping projections--reacting against the hose--and the anchoring element and anchoring member, respectively, are relatively short, which involves a relatively important effort by the user himself to perform snap closing of the clamp.
Thirdly in the known clamps the bent elastic branch of the lower arm is connected thereto through a curved portion having a relatively great curvature radius, and such that this bent elastic branch is oriented substantially perpendicularly to the lower arm. With this arrangement in the closed condition of the clamp, namely when the flexible hose fitted through the body is clamped, the elastic reaction provided by the anchoring member carried by the bent branch of the lower arm is relatively weak, which extends the risk of accidental opening under the elastic return action applied by the clamped hose against the clamping projections.
Lastly, in the known resilient clamps the curved end portion of the body connecting the lower arm and the upper arm to each other has a limited mass due in part to its reduced thickness and in part to the presence of the aperture for the hose passing through. This involves on one side a limited elastic reaction in the closed condition of the clamp, and on the other side risks of twistings and also of breakages upon closing the clamp itself.